reduction of boiler stack particulate emissions and scrubber water ...

• SCRUBBER PRESSURE DIFFERENTIAL
Set the venturi plug at a point to maintain at least 2.5 in. H 2
0 or more of pressure drop for
each venturi scrubber. The pressure drops are also continuously recorded on strip chart
recorders in the boiler control room.
BENEFITS
1. The original scrubber water flowrates had a "design" need for 800 gpm for each scrubber
system or 1600 gpm for both, which all ended up in the ash pond. This flow has now
been reduced to 200 gpm to 250 gpm for each system or 400 gpm to 500 gpm, a total
savings of 1100 + gpm.
2. By having a thicker ash bed, the combustion air entry points can be redirected to have
the undergrate air decreased as the grates are better insulated and the overfire air
increased to "lower" the flame and improve 02 addition in the suspended- burning zone.
3. With better air flow distribution, even though the BTU content of the low-sodium coal is
less than that of the previous higher-sodium coal, the combustion efficiency has
improved and coal consumption is less (about 30 + tons per day).
4. Post campaign boiler cleanup is easier and quicker, as the lower sodium coal does not
"slag" as much and the slag that does form appears softer and easier to remove.
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